Messages in this thread |  | | Date | Thu, 4 Oct 2001 00:19:13 -0400 (EDT) | From | Alexander Viro <> | Subject | Re: Security question: "Text file busy" overwriting executables but not shared libraries? |
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On 3 Oct 2001, Eric W. Biederman quoted:
> > >/* The right way to map in the shared library files is MAP_COPY, which > > > makes a virtual copy of the data at the time of the mmap call; this > > > guarantees the mapped pages will be consistent even if the file is > > > overwritten. Some losing VM systems like Linux's lack MAP_COPY. All we > > > get is MAP_PRIVATE, which copies each page when it is modified; this > > > means if the file is overwritten, we may at some point get some pages > > > from the new version after starting with pages from the old version. */
IMO it needs a slight correction.
+ /* Unfortunately, that is not an option, since losing bloatware like GNU's + relies heavily on equally bloated shared libraries and use of MAP_COPY + would eat memory with no mercy. OTOH, implementing it might be a good + idea, since results would force people to switch to something less obese */
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